Vehicle Detection and Channel Analysis of Wireless Telematics Systems
Date Issued
2009
Date
2009
Author(s)
Wang, Pao-Jen
Abstract
Abstract
In order to achieve efficient traffic control, Intelligent Transportation System (ITS) has been widely deployed in many regions such as America, Europe, Australia, Japan, and Taiwan. ITS integrates various methods to extract useful information such as the vehicle location, speed, type (a small car or a big car) etc. In addition, to manage the serious traffic problems and prevent the unnecessary personal injuries, ITS adopts the inter-vehicle communications (IVC) to inform the drivers if there are accidents nearby.
In this dissertation, we propose a channel awareness vehicle detection which employs only one single transmitter-receiver antenna pair to perform the multi-lane and multi-vehicle identifications simultaneously. By using the characteristics of channel variations, the proposed vehicle detection can determine the vehicle location, speed, and type. Our field-measurement results demonstrated its capabilities. Besides, we also propose a vehicle detection system of microwave that can extract multi-lane traffic information via using an antenna array. The proposed system adopts the multiple signal classification (MUSIC) algorithm to identify the vehicle location and speed.
Regarding to transmit the information in the IVC, the ability of effective transmission distance of the emergency information depends notably on the percentage of the vehicles equipped with communication device and the characteristics of radio wave propagation. The vehicles which are not equipped with these communication devices will block the radio propagation and result in the undesirable shadowing attenuation. Hence, we survey the impact of the shadowing effect for the IVC via the computer simulations and the field-measurements. Besides, a modified three-ray shadowing model suitable for the IVC is proposed. Finally, we use the field-measurements to evaluate the spatial diversity performance of the IVC system under different wireless channels. Combined with the three-ray shadowing model, the range extension capability by using the two receiving antennas is evaluated.
Subjects
ITS (Intelligent Transportation System)
Vehicle detector
Antenna array
IVC (Inter-Vehicle Communication)
Shadowing effect
Spatial diversity
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